This invention relates to pressure swing adsorption (PSA) processes, and more particularly to such processes employing multiple adsorbent beds.
PSA processes are well-known for the separation of gas mixtures that contain components with different adsorbing characteristics. For example, hydrogen production via pressure swing adsorption (H2 PSA) is a multi-million dollar industry supplying high purity hydrogen for chemical producing industries, metals refining and other related industries.
In a typical PSA system, a multicomponent gas is passed to at least one of multiple adsorption beds at an elevated pressure to adsorb at least one strongly sorbed component while at least one component passes through. In the case of H2 PSA, H2 is the most weakly adsorbed component which passes through the bed.
Some PSA cycles use a rinse gas during one or more steps of the cycle. Rinse gas is typically compressed. Industry desires to reduce compression requirements for PSA cycles.
Industry desires to provide an improved PSA process which increases H2 production and/or H2 recovery in a multiple bed system.